I think he means: don't put off having kids because the near-to-mid-term outlook is iffy. Your kids (he says!) won't be super expensive until the long-term, and since there's no way to know what that looks like, there's no reason to put it off.
In some ways, I disagree. I've found the expenses of children to be bathtub shaped - very expensive up front, dropping until they start public school, then ramping up slowly until they make the big jump to college.
I think putting them off makes sense because you can start investing early and people tend to earn more as they get older, so it could be less of a financial burden if you have children at an older age.
How do they ramp up until college? We saw a considerable reduction in expenses when our kid started public school, since we went from $$$ day care to $ after-school care. We expect expenses to stay somewhat the same until she hits her teenage years when she'll likely become more demanding in terms of clothes, going out with friends, etc. (at which point we plan on encouraging her to find a part-time job).
Activities become more expensive. They require more sophisticated tools and pretty much need their own computer to do homework every evening, they “need” a phone and a data plan to stay connected and do group projects, there are extracurricular activities to seem well-rounded for college applications; and halfway through high school, they start driving.
Progressive Era reforms mean it’s harder to get them to make money, but they are still expected to “volunteer” in community organizations. Many high schools require “volunteer hours” to graduate, which means you drive them to their job where they make no money and then they quit once they accumulate the mandated hours. Working in one of these community organizations, I found it pretty annoying.
In my family, we had four boys swimming competitively. So that's club fees for four, plus 20000 calories/day total if you figure each parent at 2k and each kid at 4k. My parents also paid for car insurance, which may as well be paying college tuition when you've got four young male drivers in the house.
So those are some ways. Paying for phone plans (my parents didn't) could also get expensive, as could clothes if they don't have to buy their own.
And the reality is that there's never a good time to have kids. They always will disrupt your life (in financial and non financial ways) and you can never be fully prepared for that.
There are bad times and worse times to have kids, but not good times. In your 20s you have less money but more health/personal energy. As you get older the balance shifts (hopefully!).
Really? This is fiscal advice?